Improvement of arterial blood flow, in patients with obstruction of the arteries to the leg, is usually obtained by surgically bypassing the occluded arteries, or by removing obstructions with devices that are inserted into the blood vessel. In elderly patients who have undergone multiple vascular procedures, the deterioration of arterial blood flow can lead to severe pain (ischaemic neuritis), tissue loss (arterial ulcers) or toe loss (gangrene). When the arteries of the leg cannot be repaired anymore, this situation may lead to leg amputation. Blood flow in patient's extremities, particularly the legs, markedly decreases during extended terms of confinement. Such pooling or stasis is particularly acute in surgery and during recovery periods immediately thereafter.
Diabetes is a disease where the body isn't making any or a sufficient amount of insulin and is increasingly affecting the senior and for obese members of society. Poor venous return is a symptom of this disease and affects, in particular, the lower legs and feet. Diabetes is a disease commonly associated with neuropathy.
Charcot foot is a condition causing weakening of the bones in the foot that can occur in people who have significant nerve damage (neuropathy), whereby the ability to feel temperature, pain, or trauma is diminished. Because of the diminished sensation, the patient may continue to walk-making the injury worse. Similarly to diabetic patients, those with Charcot foot should take timely action upon diagnosis otherwise the disease can ultimately lead to the loss of a toe, foot, leg or life.
There are surgical and non-surgical treatments for Charcot foot, but it will be appreciated that non-surgical treatment is preferred. Such non-surgical treatment and include immobilization—since the foot and ankle are so fragile during the early stage of Charcot, they must be protected so the weakened bones can repair themselves. Complete non-weight-bearing (off-loading) is necessary to keep the foot from further collapsing. Typically, the bones are weakened enough to fracture, and with continued walking the foot eventually changes shape. As the disorder progresses, the joints collapse and the foot takes on an abnormal shape, such as a rocker-bottom appearance.
In the past, numerous devices and methods have been disclosed for aiding cardiocepital venous flow to prevent venous hypertension. These devices and methods usually included the use of boots placed around the foot and leg and pressure was applied to the foot and leg—which are extremely cumbersome. Sufferers effectively become immobile. In addition, the prior devices did not concentrate the pressure in those areas in which it was most effective, namely, the soft tissue areas of the foot and leg, and therefore they did not operate efficiently. Further, ambulatory solutions have not been provided; there has been a need to be connected with mains supply powered stationary equipment.
Certain treatments comprise of a massager composed of a linear compressor having a piston reciprocated by force of electromagnetic attraction to produce compressed air at a safe pressure with a relatively small difference between the rated pressure and the maximum pressure, a distributor for allowing the compressed air fed from the compressor to be selectively discharged therefrom and a bag having a plurality of air tight sections which are successively expanded by receiving the compressed air fed from the distributor.
Other devices have comprised pressure-fluid massage machines and devices which have been provided with a bag means of rubber or the like, which is wound around a portion to be treated on the subject and expanded by supplying thereto a pressure fluid such as compressed air to exert massaging pressure upon the portion to be treated, thereby massaging the subject.
A patient may be fitted with a cast, removable boot, or brace, and may be required to use crutches or a wheelchair. Once fitted with a cast, blood flow will be reduced, leading to an increased likelihood of ulcers, further hampering remedial treatment of the underlying condition, bearing in mind that the condition arises through neuropathy. It may take the bones several months to heal, although it can take considerably longer in some patients. Shoes with special inserts are typically utilised after the bones have healed to enable a patient to return to daily activities, as well as seeking to prevent recurrence of the condition or associated conditions such as the development of ulcers.
The Aircast Corporation produce a diabetic walker device comprising a special form of boot which incorporates an off-loading boot a high rocker sole for maximum off-loading of the diabetic foot and a dual density insole to help eliminate pressure points. This insole, when combined with the semi-rigid shell and full air-cell coverage, also helps regulate shear stress. This design also maximises plantar offloading and is said to provide both protection and immobilisation.
U.S. Pat. No. 5,218,954 teaches of a device which operates by providing simultaneous and rapid compression of the soft tissues of the calf, ankle and foot, thereby completely and instantly emptying the veins, and reducing venous pressure to zero in a sitting patient position. Upon rapid deflation of the boot, the reduced venous pressure results in an increased driving pressure for the arterial blood flow. The increased arterial blood flow will occur approximately one second after deflation, and will last for approximately 4-14 seconds. The compression phase itself does not improve arterial flow, but impedes arterial flow; therefore compression is kept as short as possible. A stiff, non-elastic outer case for the lower leg and foot reduces the amount of fluid (air) needed to inflate the relatively small bladder. The shape of the bladder provides a contiguous connection between the foot part and the calf part, the bladder overlying the area between ankle bone and heel bone results in effective compression of the soft tissues in front of the Achilles tendon, which contain the veins draining the foot.
U.S. Pat. No. 4,502,470 provides a physiologic device having a fluid filled compartment. This is surrounded by an outer sheath fastened to the foot. The sheath holds the compartment under the instep and directs the hydraulic forces into the ankle and lower leg. Pressure produced by walking on the fluid compartment is used to compress the lower leg. This prevents swelling and it can heal ulcers due to bad veins. U.S. Pat. No. 4,624,244 teaches of a cuff for an ambulatory patient, wherein the cuff is placed around the lower calf and foot of a person suffering from circulatory problems. Air bladders are pulsated about the lower calf and soft tissue of the foot by means of a pump and pulse-inducing flow control means. The cuff does not provide a shoe as such and various fasteners are secured so that the cuffs 11 and 13 fit snugly, but not so tight as to impair circulation of a foot.
U.S. Pat. No. 4,809,684 teaches of a device and method for venous-flow stimulation, through localized periodic application of squeezing forces, essentially limited to the phalanx of the digits and thumb, and to the adjacent region of the palm of the hand. To this end, an inflatable mitt is applied to the said phalanx and adjacent regions, with digits and thumb projecting beyond the mitt. The squeeze is applied in unison circumferentially around each of the individual digits (and thumb) at the phalanx region. Alternatively, the inflatable mitt may be embedded in an orthopaedic cast, without impairing the application of pulsed pressure local to the indicated region in this case the circumferential tie is provided by the case. The arterial throughput is enhanced when the stimulating pulse is sustained for a brief period prior to a relaxation dwell between pulses. However, this system does, nonetheless need a power supply and cannot provide an integrated system.
WO0021471 (P Vinci) teaches of an in-shoe device for footdrop and is used with regular or custom-made shoes, high up to the ankle, has the purpose to correct the “steppage” coming from the deficit of foot—dorsiflexion which occurs with Charcot foot. The device has a back support in the shoe, to keep the ankle at 90°, and a pad, to protect the Achilles tendon and to permit the physiological plantarflexion.
U.S. Pat. No. 5,545,129 (K Snook) teaches of a foot cushioning device especially adapted for use by diabetic persons suffering from a protruding joint disorder of the foot in the arch or instep region includes a thick foam pad having a notch extending into the pad from one side thereof. The pad may be positioned against the sole of a person's foot with a Charcot protrusion accommodated within the notch. An elastic band of non-chafing material may be secured at a first end to the lower surface of the pad by means of hooked anchoring fabric secured to the pad.
GB2454089 (Lyndsay) describes an offloading device that provides an offloading boot wherein a sole element thereof comprises two parts which two members are moveable relative to one another, wherein movement therebetween causes a blood flow stimulating to abut gently against a plantar plexus of the under-sole of a wearer of the boot. During ambulation, the plantar plexus is compressed whereby to assist in venous and arterial drainage of the foot. Whilst this is satisfactory, when a person is walking, upon resting there is no benefit, other than that attributable to offloading. Indeed, for a person with a venous drainage condition, who is an office worker, for example, then during the passage of a day very little benefit will have been derived by the wearing of such a boot, due to the significant periods of time when the worker would have been behind a desk.
Whilst foot pressures, shock, and shear can be reduced with appropriately fitted shoes, insoles, and socks, total non-weight bearing using a wheelchair or crutches is the most effective method of relieving pressure although most patients have difficulty complying with these modalities.